Method of reducing barite in fluorspar concentrate



Patented Aug. 7, 1945 METHOD ,OF REDUCING BARITE 1N muonsmn ooncnn'rnarn Walter E. Duncan, Rosiclare, 111., asslgnor to Mahoning Mining Company, Youngstown, Ohio, a corporation of Delaware No Drawing.

Application December 24, 1943, Serial No. 515,596

Claims. (01. 209-167) My invention in general relates to flotation recovery of fluorspar from fluorspar-bearing ores and is more particularly directed to reduction of the residual amount of barite in the final con L centrates when the latter are obtained from ores 5 in which it is present in material quantities,

Many fluorspar-bearing ores contain barite (BaSOi) in amounts running up to 15% or more and when in excess of about 2% it has heretofore been substantially impossible in commercial prac- 10 tice to prevent the appearance of appreciable quantities of it in the final fluorspar concentrates'. While the presence of this residual barite isnot inimical to use of the concentrates for customary industrial purposes it nevertheless acts as a diluent, and is therefore objectionable through its lowering of the total fluorspar content of a given volume of the concentrate and particularly so when the latter is of acid-grade,-

a term generally utilized to designate a concentrate containing over 97% fluorspar (CaFz) Consequently various methods have been proposed for reducing this residual barite during treatment of ores initially containing over about 2% thereof but as far as I am aware none of I them has been highly successful in actual flotation practice, especially when considered from the standpoints of practicability, convenience and operating costs. v

I have discovered, however, that by utilization of a suitable reagent it is practicable to first remove by flotation a. very large portion of the barite in the ore and to then recover from the tailings of this flotation fluorspar concentrates devoid of barite in objectionable amounts.

A principal object of my invention therefore, is the provision of a novel method of reducing the residual barite in fluorspar concentrates produced from fluorspar ores containing substantial amounts of barite by first removing a large proportion of the latter byflotation in the presence 7 of a suitable reagent and then recovering the fluorspar from the tailings of that flotation.

My invention further comprises the use of a is first ground to a suitable fineness such as 100 mesh and then pulped and floated in water to which has been added a suitable amount of a sodium oleyl sulfate, hereinafter more particularly identified, which acts as an effective collector for the barite. with production of an extremely controllable froth in contradistinction to froths produced by those alkyl sulfates represented bythe long chain alcohol sulfates which, though powerful frothers, create froths which are watery, quite stable and not heavily mineralized. In fact, many of the froths produced by use of these other alkyl sulfates are virtually uncontrollable because of their tendency to b voluminous, to become wild and at times to make simpl almost barren suds. In contradistinction to these characteristics, however, the froth resulting from employment of the said sodium oleyl sulfate is readily controlled, heavily mineralized with' barite and easily manipulated and removed so that the tailings resulting from the flotation contain but little barite and are thus conditioned for the second step incident to the practice of the-invention, namely, flotation recovery of their fluorspar content which'may be effected by any suitable process, but preferably by that of U. S. Patent 2,168,762, granted August 8, 1939, to Clemmer and Anderson which entails, among other things, the use of quebracho extract as a depressant for the calcite content of the pulp and a fatty acid flotation reagent asa collector for the fluorspar.

As exemplifying the practice of my invention but not by way of restriction or limitation, I shall now refer to results obtained in the treatment of different ores containing, among other things, barite and fluorspar; in each case the ore was first ground to -100 mesh, a batch treatment employed in Examples I and II, and a continuous treatment in Examples III and IV.

Example I The ore utilized analyzed 'with respect to its principal constituent elements as follows: novel, reagent for, floating the barite during the initial flotation step. Per 6 1 88 Other objects, purposes and advantages of the 1421 invention will hereinafter more fully appear or cam)3 20 49 will be understood from the following description 1 20 of a preferred manner of its practice. 50

In performing the invention, ,which in com mercial usage maybe most efliciently and satisfactoril carried out as a continuous operation through suitable arrangement of the various flotation cells and other apparatusyemployed and 5 V which may be of any suitable character, the ore no sulfides being present. The barite was floated first, using soft water towhichfor the rougher circuit hadbeen added 1.0 lb. of the sodium oleyl sulfate, 2.0 lbs. sodium silicate, 0.48 lb. citric acid and 1.0 lb. barium chloride per ton of feed;v the concentrate was then cleaned three times in a cleaner circuit with soft water containing 1.3 lbs. sodium silicate per ton of feed. The fluorspar in the tailings of the barite flotation was next floated inaccordance with the practice disclosed in said A continuous instead of batch treatment was employed, the barite being floated first using soft water to which, for the rougher circuit, had been added. 2 lbs., sodium silicate and 0.5 lb. sodium Patent 2,168,762 using soft water to which, for the 5 oleyl sulfate per ton of feed and the concenrougher circuit, had been added 1.0 lb. soda ash, trates obtained were cleaned in a cleaner circuit 2.0 lbs. oleic acid and 2.0 lbs. quebracho extract using soft water containing 1.2 lbs. sodium silicate per ton of feed, and the concentrate was then per ton of feed. The tailings following this treatcleaned four times in a cleaner circuit using soft ment were then floated for fiuorspar in accordwater containing 3.0 lbs. quebracho extract per Hi ance with the practice disclosed in said Patent ton of feed. The following results were obtained:- 2,168,726, using soft water to which, for the rougher circuit, had been added 0.32 lb. oleic Assay,v Mineral distribu. acid, 0.6 lb. of sodium carbonate and 1.5 lbs. queperoent tiompercent bracho extract per ton of feed. The concenlb trates were then cleaned in a cleaner circuit using B950 CBFi B8804 CBFi soft water containing 1.8 lbs. quebracho extract per ton of feed. The following results were ob- Fced 1- 14.21 61.90 tamed; Barite flnalcoucentrate 96.4 1.3 87.9 0.3 1

2Fi$3titan1ar 5 5%; 93'? ii; A I m SSGY, 111818 S 1 l1- 5133.232? itlfilliti gffiiiiiii 3:53 33:33 812 3:? Fluorspar rougher concencitfis'jjiiiiiji .1: 312% 33% ti? &1? B850 B350 Composite 14.2 01.2 100.0 100.0

- Feed 17.0 01.1

Barite iinalconcentrat 71.3 18.4 92.4 7.0 Example 11 Baritetailings 1.8 74.0 7.6 03.0 Fluorspar final concentrates.. 0. 8 92. 9 2. 5 88. 4 The ore utilized analyzed with respect to its Fluorspar finaltailings 19 140 5.1 4.0 principal constituent. elements as follows:

Per t m Example IV The ore utilized analyzed with respect to its B9504 principal constituent'elements as follows: CaCO3 Per cent CaFz 63.88 Pb BaSO1 9.30 --f-- CaCOs 1.50 Again the barite was floated first, using soft water sioz 11-68 to which for the rougher circuit had been added 0.66 1.0 lb. sodium oleyl sulfate, 2.0 lbs. sodium silicate, b 1.0 lb. barium chloride and 0.5 lb. citric acid per 40 A5 in Example 111 the iwas floated first ton of feed? the concentrate was n cleaned using soft water to which for the rougher circuit three times in a cleaner circuit with soft water had been added 05 Sodium oleyl ulf te 1 containing sodium Silicate P n of feedlbs. sodium silicate, 1.0 lb. soda ash and 0.5 lb. The fluorspar in the tailings of the barite flotation citric acid per ton of feed and the concentrate was next floated as in Example I using soft water was cleaned in a cleaner circuit using soft water to whichfor the rougher circuit, had been added containing 0.07 lb. sodium silicate. The tailings lbfifioda ash, L0 Olelc Field following this treatment were then floated for quebracho extract per ton of feed and the concenfluorspar asin h example using soft water to was e cleaned three times in cleaner which for the rougher circuit had been added circuit using soft Water containing 1.15 lbs. oleic acid and 0.9 lb uuebracho extract bracho extract per ton of feed. The following per ton v feed and were 'then cleaned in a results were obtamed: cleaner circuit using soft water containing 0.30

lb. quebracho extract per ton of feed. The fol- ASSBY' MiPmldistribulowing results were obtained: per cent tlon, per cent lasso. car, lasso. can f j jgj iiti'ttiiaiaaaiazsj::3: $315? 3327 56.9 0.5 B980 B880 W1 Barite middlings 11.50 02.3 15.8 10.3 tiitiiti fiffifiiifi at. .92 i Fluorspar middlings 1: 28 59: 24 1:4 7:9 322: ggl i g f i f f f f mughe' O 5 85 0 2 1 80 8 Fluorspar iinslc'o iltrati 0150 96:34 218 83:0 26:78 11:68 Fluorspar finaltalllngs 2.16 20. 78 8.9 16.7 13.90 02.50 100.00 100.00 The sharpness of separation effected by the Exam le 111 flotation in the presence of'the sodium oleyl sul- The ore utilized analyzed with respect to its Egg fifigf i g ii g gj zig g gfiff ggi pfmclpalcPnstltuemelemems asf0110ws- 7o content of 61.90% in the feed, the barite final Per cent concentrate; showed only 1.3% CaFz against CaF V 61.1 96.4% B2504 in Example I;with a barite content B2504 -1 17.9 0f-13.9% and a fiuorspar content of 62.5% in the CaCOz 16.7 feed, the barite final concentrate showed only 2 1.1 3.77% CIlFz against 92.14% BaSO; in Example 11,

l i i fluorspar in the feed.

while in Example III with 17 .9% barite and 61.1% fluorspar initially present, the barite final concentrate. showed 18.4% Cam against 71.3% M804, and in Example IV, 1.75% Car: and 91.84% B3804 against 9.30%,barite and 63.88%

It will be noted that inExamples I and H small amounts of citric acid and barium chloride were used in the flotation of the barite and in Example III a small amount of citric acid, but these reagents are not essential for satisfactory results although sometimes desirable to eliminate the necessity for protracted cleaning; thus the advantages obtainable by the use of the invention are in no way dependent on the presence or absence of these reagents in the barite flotation since results comparable to those given in these examples may be obtained in their absence by merely increasing the number of cleanings prior to the flotation for fluorspar.

As far as I have been able to determine by extended research, optimum results in reduction of residual barite in the final fluorspar concentrate are obtainable only by employment of sodium ole l sulfate responding to the formula c (CH2) 7CH=CH CH2 'zCHzOsOaNa which inay be partially written structurally as H -Na cnl(cn. 1cn=cn cn, 1.+-s=0 and which is exemplified by materials now marhated by E. I. du Pont de Nemours & Company and by Onyx Oil and Chemicals Company respectively under the trade names or brands Duponol LS" and Aurinol," this particular sodium oleyl sulfate whergused as a collector apparently tending td form diflicultly soluble compounds with thebarite but not with the calcium minerals such as fluorspar and calcite (CaCOa) present in the ore; the advantageous characteristics of the froth engendered by its use have already been mentioned. i As hitherto pointed out, whenthe barite content of the feed ore is not materially in excess of about 2% recovery of a final fluorspar concentrate with but a comparatively small amount of resi l barite can be obtained by flotation of the tably 'und ore in accordance' with the disclosure laid Patent 2,168,762, probably because wi his high ratio (from about :1 and up) of fluorspar to barite the latter is starved or crowded out during the flotation for fluorspar and forced into the tailings. But when the barite is in excess-of the amount mentioned this effect is not sufficient to enable the production of a flnal fluorspar concentrate containing but little residual barite. It therefore seems reasonable to assume that a somewhat similar result takes place when in accordance with the present invention sufficient of the barite is removed by the initial flotation to establish a barite-fluorspar ratio in the tailings of the order just mentioned. thus enabling a material part of the remaining barite to be starved or crowded out during the ensuing flotation for fluorspar with consequent reduction to a minimum of the residual barite in the final concentrate. It follows that the present invention is of maximum utility when the barite content of the ore exceeds about 2% as by its employment a final fluorspar concentrate of acid or substantially acid-grade can readily be produced from ore of that character.

In the aforesaid examples soft water was emsoften it by means of a lime-soda or a zeolite treatment, although successful practice of the invention is not dependent upon the use of water of zero or-substantially zero hardness. I also prefer to maintain the pH in the flotation circult between 8.0 and 8.6 but it isto be understood this range'is stated merely asindicative of the best way I have found of practising'the invention and not as constituting a limitation upon it.

Moreover, while I have herein described my invention with considerable particularity and have given certain examples of its practice, it will be understood that I have done so only for purposes of illustration and not with a view to limiting or restricting it in any manner, as other ways of performing it in accordance with differing operating conditions or with ores of various characters will readily occur to those skilled in the art and may be utilized if desired without departing from the spirit and scope of the invention as defined in the appended claims.

Having thus described my invention, I claim and desire to protect by Letters Patent of the United States:

1. The method of reducing residual barite in fluorspar concentrates derived from ores containing barite in excess of about 2%, which comprises pulping the ground ore with water, floating the pulp in the presence of sodium oleyl sulfate of the formula CH3 (CH2) 7CH=CH(CH2) 7CH2OSOaNa collecting the barite concentrates resulting from said flotation and subjecting the flotation tailings to agitation in the presence of a soap forming higher fatty acid and quebracho extract to thereby poncentrate the fluorspar and induce a further separation therefrom of residual barite in said tailings.

2. In the recovery of fluorspar concentrates by flotation from fluorspar-bearing ores containing barite in excess of about 2%, the steps of pulping the ground ore with water containing sodium oleyl sulfate of the formula CH3(CH2) 7CH=CH (CH2) wcmosoma and agitating the mixture to produce a baritebearing froth, removing said froth and then agitating the tailings of said flotation in the presence of a fatty acid of more than twelve carbon atoms and quebracho extract to thereby form a fluorspar-containing froth and induce further separation between the barite and fluorspar in said tailings.

3. In the recovery of fluorspar concentrates by flotation from fluorspar-bearing ores containing barite in excess of about 2%, the steps of pulping the ground ore with water containing sodium oleyl sulfate of the formula CH: CH2) 7CH=CH(CH2) rCHaOSOaNa and agitating the mixture to produce a baritebearing froth, removing said froth and then agitating the tailings of said flotation in the presence of a fatty acid of more than twelve carbon atoms and quebracho extract to thereby form a fluorspar-containing froth and induce further separation between the barite and fluorspar in said tailings, removing the froth and recovering the fluorspar concentrate therefrom.

4. In the production of fluorspar concentrates from fluorspar-calcite-bearing ores containing barite in an amount exceeding about 2%, the

steps of first pulping the ground ore with water containing sodium oleyl sulfate of the formula agitating the mixture to produce a barite-bearing froth, removing said-froth, and then recovering fluorapar concentrates from the tailings of said notation by flotation concentration in the presence of a soap forming higher fatty acid and a tannin containing calcite depressing reagent;

5. That method of reducing the residual barite in iiuorspar flotation concentrates derived from iiuorspar-bearing ores containing barite in excess of about 2%, which comprises first pulping the ground ore with water containing per ton of feed about 2 lbs; oi

crmcm) CH=CH CH2) 1CH=OSO1N a as a collector for the barite, agitating the mixture to produce a barite-containing forth, removing the froth, and then subjecting the tailings of the flotation to flotation concentration in the presence oi. oleic acid and quebracho extract to recover concentrates therefrom containing Cal:

and residual barite not exceeding about 2%.

WALTER E. DUNCAN. 

